f(a)=(2sina*cosa+5/2)/(sina+cosa) a属于[0,90度] 求f(a)最小值
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f(a)=(2sina*cosa+5/2)/(sina+cosa) a属于[0,90度] 求f(a)最小值
f(a)=(2sina*cosa+5/2)/(sina+cosa) a属于[0,90度] 求f(a)最小值
f(a)=(2sina*cosa+5/2)/(sina+cosa) a属于[0,90度] 求f(a)最小值
f(a)=(2sina*cosa+1+3/2)/(sina+cosa)
=((sina+cosa)^2+3/2)/(sina+cosa)
=(sina+cosa)+(3/2)/(sina+cosa)
(sina+cosa)=[0,√2]
额···最后一步写错了,惭愧
改为:
设sina+cosa=t
g(t)=t+(3/2)/t (这个函数认识吧)
显然当t=√(3/2)时 g(t)取最小值√6